JP2011046353A - Hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hybrid vehicle which causes an engine to be operated by setting a request driving force to a target driving force when the request driving force is larger than a determination value, thereby maintaining satisfactory driving performance without deteriorating driving force even in starting an engine having large request driving force, and which allows reduction in fuel consumption. <P>SOLUTION: A control means (12) controls an engine (1) and motor generators (4, 5) so that a request driving force set by a request driving force setting means (29) is obtained, and causes the engine (1) to be operated by setting the request driving force to a target driving force when the request driving force is larger than a determination value by comparing the request driving force with a preset determination value. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hybrid vehicle, and more particularly to a hybrid vehicle that includes a plurality of power sources, synthesizes these powers, and outputs them to a drive shaft.

There is a so-called hybrid vehicle including an engine and a motor generator (electric motor) in addition to the engine as a drive source. The hybrid vehicle equipped with this engine and motor generator can be used in the power system of the series system (the engine is used only for turning the generator, and all the driving is performed by the motor generator: series system) or the parallel system ( There is a system in which an engine and a motor generator are arranged in parallel, and each power is used for driving: a parallel system).
Further, in the hybrid vehicle, other power utilization methods include a three-shaft type engine using one planetary gear mechanism (differential gear mechanism having three rotating elements) and two motor generators. The power of the engine is divided into a generator and a drive shaft, and a motor generator provided on the drive shaft is driven using the electric power generated by the generator to convert the engine power to torque. The operating point is set to an arbitrary point including a stop to improve fuel efficiency.

Japanese Patent Laid-Open No. 2005-163551 JP, 2006-306371, A The power output device which relates to patent documents 1, its control method, and the car carrying this are detected when the engine operation is stopped and the power from the electric motor is outputted to the drive shaft. The power output to the drive shaft based on the starting state is output with a smooth change, and the starting means and the electric motor are drive-controlled so as to start the engine. The vehicle and its control method according to Patent Document 2 set a required driving force based on an operation by an operator, and when the set required driving force is accompanied by a change that is less than a predetermined change amount, A target driving force that is increased or decreased within the range of the first change allowable value is set, and when the set required driving force is changed by a predetermined amount or more, the required driving force is maintained over the predetermined time. A target driving force that is increased or decreased within the range of the second change allowable value that is smaller than the first change allowable value is set, and the first change allowable value is set toward the required drive force after a predetermined time has elapsed. The target driving force increased or decreased within the range is set, and the driving device is controlled so that the set target driving force is output from the driving device to the drive shaft.

However, although not as much as the series system, a motor generator having a relatively large torque is required to obtain a sufficient drive shaft torque, and between the generator and the motor generator in the LOW gear ratio range. As the amount of power delivered in the country increased, the electrical loss increased and there was still room for improvement.
As a method for solving this point, as a four-shaft type, each rotating element of a power transmission mechanism (differential gear mechanism) having four rotating elements includes an engine output shaft, a first motor generator, and a second motor. There is a structure in which a generator and a drive shaft connected to the drive wheel are connected, and the engine power, the power of the first motor generator, and the power of the second motor generator are combined and output to the drive shaft. Then, the engine output shaft and the drive shaft are arranged on the inner rotary element on the alignment chart, and the engine-side first motor generator and the drive shaft-side second are arranged on the outer rotation element on the alignment chart. By arranging the motor generator, the proportion of the power transmitted from the engine to the drive shaft by the first motor generator and the second motor generator is reduced, and the first motor generator and the second motor generator are reduced. In addition to downsizing, transmission efficiency as a drive device is improved.
JP 2002-281607 A

  By the way, in a conventional hybrid vehicle equipped with a four-shaft type power transmission mechanism, a reverse reaction torque acts on the drive shaft to crank the engine when the engine is started. In some cases, the driving force at the time of starting becomes smaller than the driving torque when traveling at a low speed, and when the driving force temporarily decreases due to the start of the engine, the driving performance becomes jerky. In particular, when the engine is started with the required driving force increased by depressing the accelerator pedal, the engine is cranked in order to start the engine even though the driver intends to increase the driving force. At times, the driving force temporarily decreases, and there is a disadvantage that the uncomfortable feeling becomes remarkable.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a hybrid vehicle that maintains good driving performance without reducing driving force even when an engine having a large required driving force is started, and that reduces fuel consumption.

  The present invention provides a hybrid vehicle that outputs power generated from an engine and a motor generator to a drive shaft via a power transmission mechanism, and includes a required drive force setting unit that sets a required drive force in response to a driver's request. There is provided control means for controlling the engine and the motor generator so that the required driving force set by the required driving force setting means is obtained, and the control means compares the required driving force with a preset determination value. Then, when the required driving force is larger than the determination value, the required driving force is set as a target driving force, and the engine is operated.

  The hybrid vehicle of the present invention reduces the driving force even when the engine having a large required driving force is started by operating the engine with the required driving force set as the target driving force when the required driving force is larger than the determination value. If the required driving force is smaller than the determination value, the engine is not operated, so that the fuel consumption can be reduced.

FIG. 1 is a system configuration diagram of a control apparatus for a hybrid vehicle. (Example) FIG. 2 is a block diagram of the control means. (Example) FIG. 3 is a flowchart of control in the control means. (Example) FIG. 4 is a diagram showing a requested driving force search map. (Example) FIG. 5 is a diagram showing a travel mode area. (Example) FIG. 6 is a diagram showing a driving force pattern. (Example)

The present invention requires the purpose of maintaining good driving performance without lowering the driving force even when starting an engine having a large required driving force and reducing the fuel consumption when the required driving force is larger than a judgment value. This is realized by setting the driving force to the target driving force and operating the engine.
Hereinafter, embodiments of the present invention will be described in detail and specifically with reference to the drawings.

1 to 6 show an embodiment of the present invention.
In FIG. 1, 1 is an engine mounted on a hybrid vehicle as a vehicle, and 2 is a control device for the hybrid vehicle.
The control device 2 includes an output shaft 3 of an engine 1 that is a driving source for outputting torque, a first motor generator 4 and a second motor generator 5 as motor generators, and a transmission gear mechanism 7 for driving wheels 6. And a power transmission mechanism (differential gear mechanism) 9 coupled to the output shaft 3, the first motor generator 4, the second motor generator 5, and the drive shaft 8, respectively. ing.
The control device 2 also includes a first inverter 10 that controls the operation of the first motor generator 4, a second inverter 11 that controls the operation of the second motor generator 5, the first inverter 10, and the second inverter Control means 12 communicated with the inverter 11 is provided. Each power supply terminal of the first inverter 10 and the second inverter 11 is connected to the battery 13.

  The power transmission mechanism 9 is a so-called four-shaft power input / output device, which includes the output shaft 3 and the drive shaft 8 of the engine 1, and the first motor generator 4 on the engine 1 side and the drive shaft 8 side. The second motor generator 5 is arranged, the power of the engine 1, the power of the first motor generator 4 and the power of the second motor generator 5 are combined and output to the drive shaft 8, and the engine 1 and the first motor generator 5 are combined. Power is transferred between the first motor generator 4, the second motor generator 5, and the drive shaft 8.

The power transmission mechanism 9 is configured by arranging a first planetary gear mechanism 14 and a second planetary gear mechanism 15 in which two rotation elements are connected to each other.
The first planetary gear mechanism 14 includes a first sun gear 16, a first pinion gear 17 that meshes with the first sun gear 16, and a first ring gear 18 that meshes with the first pinion gear 17. And a first carrier 19 connected to the first pinion gear 17.
The second planetary gear mechanism 15 includes a second sun gear 20, a second pinion gear 21 that meshes with the second sun gear 20, and a second ring gear 22 that meshes with the second pinion gear 21. , And a second carrier 23 connected to the second pinion gear 212.

In the power transmission mechanism 9, the first carrier 19 of the first planetary gear mechanism 14 is connected to the output shaft 3 of the engine 1, and the second carrier 23 of the second planetary gear mechanism 15 is The first planetary gear mechanism 14 is connected to the first ring gear 18.
A first motor generator 4 is connected to the first sun gear 16 via a first motor output shaft 24. The output shaft 3 of the engine 1 is connected to the first carrier 19 and the second sun gear 20. The drive shaft 8 is connected to the first ring gear 18 and the second carrier 23 via the transmission gear mechanism 7. The second motor generator 5 is connected to the second ring gear 22 via the second motor output shaft 25.
The second motor generator 5 is configured to drive wheels via a second motor output shaft 25, a second ring gear 22, a second carrier 23, a first ring gear 18, a transmission gear mechanism 7, and a drive shaft 8. 6 can be directly connected to the vehicle, and the vehicle can be driven only by a single output.
That is, in the power transmission mechanism 9, the first carrier 19 of the first planetary gear mechanism 14 and the second sun gear 20 of the second planetary gear mechanism 15 are coupled and connected to the output shaft 3 of the engine 1. The first ring gear 18 of the first planetary gear mechanism 14 and the second carrier 23 of the second planetary gear mechanism 15 are coupled and connected to the drive shaft 8, and the first planetary gear mechanism 14 The first motor generator 4 is connected to one sun gear 16, the second motor generator 5 is connected to the second ring gear 22 of the second planetary gear mechanism 15, the engine 1, the first motor generator 4, Power is exchanged between the second motor generator 5 and the drive shaft 8.

As shown in FIG. 2, the control means 12 communicates with a vehicle speed sensor 26 that detects the vehicle speed and an accelerator sensor 27 that detects the amount of depression of the accelerator pedal as the accelerator opening, and the required driving force according to the driver's request. Required driving force setting means 28 for setting the driving mode, traveling mode determination means 29 for contacting the required driving force setting means 28 and determining the traveling mode from the determination value (threshold value) of the traveling mode, and the traveling mode determination A determination value storage means 30 for contacting the means 29 and preliminarily storing the determination value of the travel mode; a target drive force calculation means 31 for contacting the travel mode determination means 29 and the determination value storage means 30 and calculating a target drive force; It has.
The control means 12 outputs a predetermined control value for operating the first motor generator 4 and the second motor generator 5 to control the operation of the first inverter 10 and the second inverter 11, as well as the engine 1. To control the operation.
The battery 13 has a function of storing electricity when the first motor generator 4 and the second motor generator 5 are regenerated.

The control means 12 controls the engine 1 and the first motor generator 4 and the second motor generator 5 so that the required driving force set by the required driving force setting means 28 is obtained. When the required driving force is larger than the determination value by comparing with the set determination value, the engine 1 is operated with the required driving force set as the target driving force.
Further, the control means 12 sets the determination value to a value less than or equal to the driving force that can be output during the start of the engine 1, and limits the target drive force to a value equal to or less than the determination value when the engine 1 is started.
That is, in the hybrid vehicle control apparatus 2 according to this embodiment, the engine 1 is stopped and the first motor generator 4 and the second motor generator 5 operate the engine 1 from the traveling mode to shift to the traveling mode. As a condition to perform, the required driving force calculated based on the accelerator opening (depressing amount of the accelerator pedal) exceeds a determination value set as a value smaller than the driving force that can be output during the start of the engine 1. It is configured to limit the target driving force so as not to be larger than the determination value during startup of the engine 1, and is further configured to release the limitation on the target driving force after the startup of the engine 1 is completed. .

For this reason, as shown in FIG. 4, the control means 12 incorporates a required driving force (target driving force) search map. In the required driving force search map of FIG. 4, when the vehicle speed is V1 which is increased from zero (0) to a predetermined value and the accelerator opening is 0% or less, the required driving force is set to a negative value. When the opening degree is 50% and 100% and the vehicle speed is V2, which is larger than V1, the required driving force is set to gradually decrease at a positive value.
Further, in the control means 12, a travel mode area is set as shown in FIG. In the travel mode region of FIG. 5, when the accelerator opening is between 0% and the accelerator opening is 100%, the driving force judgment value (shown by a solid line) of the present case is the conventional judgment value (shown by a broken line). Is set to a lower value, and the vehicle speed exceeds V1 and V3 is greater than V2, and the engine mode region in which the engine 1 is operated and the first motor generator 4 and the second motor generator 5 are operated. The EV (electric vehicle) mode area is set.

Next, the operation of this embodiment will be described based on the flowchart of FIG.
As shown in FIG. 3, when the program of the control means 12 is started (step A01), first, various signals are fetched (step A02), and a request corresponding to the vehicle speed and the accelerator opening is obtained from the required driving force search map of FIG. A driving force is set (step A03), and it is determined whether or not the required driving force exceeds a determination value (step A04). Here, in the case of a high vehicle speed range with the accelerator opening = 0%, as shown in FIG. 4, a negative value is set so that the driving force is in the deceleration direction equivalent to the engine brake, and the accelerator opening ≠ In the case of a low vehicle speed range of 0%, a positive value is set so that creep driving can be performed. The determination value is set to be equal to or less than the driving force that can be output when the engine 1 is started, and is set to a value that does not decrease the driving force when the engine 1 is started.
If this step A04 is YES and the required driving force exceeds the determination value, the engine mode is set (step A05), it is determined whether or not the engine 1 has been started (step A06), and this step A06. Is YES and the start of the engine 1 is completed, the required driving force is set as the target driving force (step A07).
On the other hand, if step A04 is NO and the required driving force does not exceed the determination value, the EV mode is set (step A08), and the smaller value (minimum value) of the required driving force and the determination value is set. ) As a target driving force (step A09). Further, even when the step A06 is NO and the start of the engine 1 is not completed, the smaller value (minimum value) of the required driving force and the determination value is set as the target driving force (step A09). .
After the process of step A07 or after the process of step A08, the program is returned (step A10).
Thus, as shown in the driving force pattern of FIG. 6, when comparing the relationship between the vehicle speed and the driving force when the vehicle is started with the accelerator opening fully opened from the vehicle stop state, the accelerator opening is greatly reduced by depressing the accelerator pedal greatly. In the case of starting the engine 1 with the engine speed increased, the driving force has been temporarily reduced after the driving force has increased (indicated by a thick broken line in FIG. 6). However, in the present plan, the driving force does not decrease. Good driving performance can be maintained (indicated by a thick solid line in FIG. 6).

As a result, in this embodiment, the required driving force according to the driver's request is compared with a preset determination value, and when the required driving force is larger than the determination value, the required driving force is set to the target driving force. Therefore, when the required driving force is smaller than the determination value, the engine 1 does not operate and the fuel consumption can be reduced.
Further, when the required driving force is larger than the determination value, the required driving force is set to the target driving force and the engine 1 is operated. Since the target driving force is limited to a value equal to or less than the determination value when the engine 1 is started, the driver further updates the vehicle while traveling by the first motor generator 4 and the second motor generator 5. When acceleration is required, it is necessary to add power from the engine 1, and in this case, it is necessary to start the engine 1 that has been stopped. Even when starting the engine 1 is started, That is, even when the engine having a large required driving force is started, the driving force is not temporarily reduced during cranking of the engine 1, which can contribute to improvement of driving performance.

  The hybrid vehicle control device according to the present invention can be applied to various vehicles.

DESCRIPTION OF SYMBOLS 1 Engine 2 Control apparatus of hybrid vehicle 3 Engine output shaft 4 1st motor generator 5 2nd motor generator 8 Drive shaft 9 Power transmission mechanism 10 1st inverter 11 2nd inverter 12 Control means 13 Battery 14 1st Planetary gear mechanism 15 second planetary gear mechanism 26 vehicle speed sensor 27 accelerator sensor 28 required driving force setting means 29 travel mode determination means 30 determination value storage means 31 target driving force calculation means

Claims (2)

  In a hybrid vehicle that outputs power generated from an engine and a motor generator to a drive shaft via a power transmission mechanism, the vehicle is provided with required drive force setting means for setting required drive force according to a driver's request. There is provided control means for controlling the engine and the motor generator so that the required driving force set by the setting means is obtained, and the control means compares the required driving force with a predetermined determination value to compare the required driving force. A hybrid vehicle characterized in that when the driving force is larger than the determination value, the engine is operated with the required driving force set as a target driving force.   The control means sets the determination value to a value less than or equal to the driving force that can be output during engine startup, and limits the target driving force to a value less than or equal to the determination value when the engine is started. The hybrid vehicle according to claim 1.

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